Journalists in post-revolution Libya face the constant threat of attack and have lost even the limited freedom that existed under dictator Muammar Gaddafi, Human Rights Watch said on Monday.

A 54-page report by the New York-based rights watchdog released in Tunisia said journalists in Libya are "assaulted, kidnapped and killed with impunity.”

"Journalists were among the 250 people killed in apparent politically motivated assassinations in 2014," HRW said in the report entitled "War on the media: journalists under attack in Libya.”

It also documented "at least 91 cases of threats and assaults against journalists, 14 of them women, from mid-2012 until November 2014,” including 30 kidnappings and eight killings.

HRW reported "26 armed attacks" against media headquarters over the same period.

It said evidence suggests that "the armed groups sought to punish journalists and media outlets for their reporting, their opinions, or their perceived sympathies."

HRW blamed authorities for failing to protect journalists, and said this "has wiped out much of the limited freedom that existed following the 2011 uprising" that toppled and killed Gaddafi.

"Authorities failed to hold anyone accountable for attacks on journalists and media outlets since 2012," it said, while "courts are prosecuting people, including journalists, for speech-related offenses.”

The situation worsened last year sparking an exodus of journalists, said HRW, while those who chose to stay have been forced into self-censorship.

"The climate of impunity has allowed militias to assault, threaten, kidnap, or even kill journalists because of their reporting or views," said HRW's deputy Middle East and North Africa head Joe Stork.

"Government authorities and non-state actors who control territory should urgently condemn attacks on journalists and where possible hold those responsible to account," he added in the report.

HRW researcher Hanan Saleh denounced a "culture of impunity.”

"Many journalists don't want to report (aggressions they experienced) to the police because they don't think that the police or the judiciary can help them or do them justice," she told reporters in Tunis.

HRW cited several examples of media being targeted in Libya, including the separate murders last year in Benghazi of journalist Miftah Bouzeid, whom it said was a "prominent critic" of Islamist militias, and radio broadcaster al-Mutassim al-Warfalli, who it said supported them.

The North African nation has been wracked by conflict for the past four years, with rival governments and powerful militias battling for control of key cities and the country's oil riches.

Western military intervention in Libya in 2011 brought with it an influx of weapons, with Gulf Arab states also supplying arms to rebels, many of whom now refuse to hand them over to the internationally recognized government headed by Prime Minister Abdullah al-Thani.

Last August, Thani and his cabinet were forced to leave Tripoli for the east when militants from Fajr Libya (Libyan Dawn) seized the capital. The new rulers of Tripoli have set up their own administration, the General National Congress (GNC), which has not been recognized by the United Nations and world powers.

Libya's violence has drawn strong condemnation from both the UN and European Union, and rights group Amnesty International has accused several factions of war crimes.

According to Amnesty, militants in the west showed “an utter disregard” for civilian casualties and accused them of indiscriminately lobbing artillery fire into crowded civilian neighborhoods, damaging homes and hospitals.